He said: "This GRU operation was trying to collect information about the MH17 investigation".
Britain says Russia's military intelligence agency, the GRU, attacked a wide range of civilian and political targets in what it calls a "flagrant violation of global law".
But Russian Foreign Ministry spokeswoman Maria Zakharova dismissed the new accusations on Thursday, calling them "big fantasies". But the accusations will deepen Moscow's isolation at a time when its diplomatic ties with the West have been downgraded over the poisoning of a spy in England and it is under US and European sanctions over its actions in Ukraine.
London has also accused two of GRU's officers of poisoning former double-agent Sergei Skripal and his daughter in the British city of Salisbury in March, using a perfume bottle containing a powerful nerve agent.
Russian military intelligence (GRU) used a network of hackers across the world to attack a wide range of targets, including the Organization for the Prohibition of Chemical Weapons (OPCW) in the Netherlands and the UK's Foreign and Commonwealth Office, the UK's National Cyber Security Centre (NCSC) said. The Justice Department said one of the Russians performed reconnaissance of personnel and stole log-in credentials at the company.
It has agents across the globe and answers directly to the chief of the general staff and the Russian defence minister. "The online environment is not the Wild West and the worldwide rules apply", said Prime Minister Scott Morrison.
US Secretary of Defence James Mattis speaks during a news conference after North Atlantic Treaty Organisation defence ministers meeting at the Alliance headquarters in Brussels, Belgium.
"The International Community - including Russian Federation - has agreed that international law and norms of responsible state behavior apply in cyberspace", Australia's Prime Minister Scott Morrison said.
Australia and New Zealand supported Britain's assessment of the GRU and pledged to improve cooperation on responses to cyber attacks.
Ryabkov's statement repeated a pattern of Russian Federation denying serious allegations made by the West and attributing them to a Western plot against Moscow.
Britain accused Russian military intelligence on Thursday of directing a host of cyber attacks aimed at undermining Western democracies by sowing confusion in everything from sport to transport and the 2016 US presidential election.
They had planned to travel on to a laboratory in Spiez, Switzerland used by the OPCW to analyse chemical weapons samples, he said. They were expelled to Russian Federation.
Britain said the GRU was associated with a host of hackers including APT 28, Fancy Bear, Sofacy, Pawnstorm, Sednit, CyberCaliphate, Cyber Berkut and Voodoo Bear.
A joint statement from British Prime Minister Theresa May and her Dutch counterpart Mark Rutte said the alleged plot demonstrated "the GRU's disregard for global values and rules that keep us all safe".
The GRU's actions are reckless and indiscriminate: they try to undermine and interfere in elections in other countries.
"It is evident from the allegations in today's indictment that the defendants believed that they could use their perceived anonymity to act with impunity", John Demers, the U.S. assistant attorney general for national security, said at a press conference announcing the charges.
The OPCW was at the time probing the nerve agent poisoning of Russian ex-spy Sergei Skripal in the English town of Salisbury, and an alleged chemical attack on the Syrian town of Douma by the Moscow-backed regime in Damascus.